20 April 2021
This EAGE E-Lecture: "Assessing the link between EMI data and hydrocarbon pollution at a former refinery site" Brownfield redevelopment is an answer to create potential building areas inside cities and avoid urban sprawl. However, soils and groundwater in place have often been contaminated by former activities. Environmental assessments (EA) are thus necessary to characterize and estimate the contaminated volume of soils and the site rehabilitation cost. Nevertheless, classical investigation techniques (boreholes, piezometers, sample analysis) can only provide punctual observations and are cost and time intensive. Electromagnetic induction (EMI) methods in the frequency domain can complement these investigations and map electromagnetic soil properties (soil-apparent electrical conductivity and in-phase component) in a quasi-continuous way at a site scale. Linking these indirect geophysical properties to the soil chemical analysis through a geostatistical modelling could provide a better quantification of the pollution source and its spreading. Besides, the effect of urban EMI noises from urban utilities (transmission wires, underground cables and structures…) must be assessed for a successful data fusion. To evaluate the feasibility of this geophysical-geochemical-geostatistical approach, we present the first results of a study conducted over a 3 000 m² brownfield site.